Next-generation sequencing (NGS) allows small-scale, inexpensive genome sequencing with a turnaround time measured in days. However, as NGS is generally performed and understood, all regions are sequenced with roughly equal probability, meaning that a large amount of genomic sequence is collected and discarded to collect sequence information from the relatively low percentage of areas where function is understood well enough to interpret potential mutations. Generally, purifying from a full-genome sample only those regions one is interested in is conducted as a separate step from sequencing. It is usually a days-long, low efficiency process in the current state of the art.
Next generation sequencing of nucleic acids has greatly increased the rate of genomic sequencing, thereby bringing in a new era for medical diagnostics, forensics, metagenomics, and many other applications. However, these high-throughput approaches often incorporate errors, resulting in inaccuracies in a constructed consensus sequence. These errors can arise, for example, during nucleic acid amplification or sequencing, or downstream analysis. Additionally, errors can arise due to chemical damage of the original nucleic acid molecule. In some cases, as many as 1% of sequenced bases can be incorrectly identified. These errors in the nucleic acid consensus sequence limit the reliability of known NGS methods.
Direct Targeted Sequencing (DTS) is a modification to the standard sequencing protocol employed by Illumina, Inc. that allows the sequencing substrate (i.e., the flow cell) to become a genomic sequence capture substrate as well. Without adding another instrument to the normal flow of a typical NGS protocol, the DTS protocol modifies the sequencing surface to capture genomic DNA (gDNA) from a specially prepared library. The captured library is then sequenced as a normal gDNA library would be. However, modification of the sequencing substrate and accompanying library preparation according to previous suggestions result in inefficiencies, reduced reliability and reproducibility, and waste valuable sample. Improvements to the DTS process are therefore desirable.